307 research outputs found

    A produção racional em regime histĂłrico de fĂ©: com vistas Ă  ciĂȘncia

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    Because of the difference of their own pertinences, there is no possible direct dialogue between science and theologal faith. Indeed, there is nothing strange in this, because the same occurs between one science and another, between one science and philosophy and even between science and general culture. Each science is a close structure, and it speaks only its own language, ignoring all the others. But it does not mean that the dialogue among several kinds and genera of discourses is impossible. It is the interpreter's mediation that makes it possible, and philosophy is its privileged place and agent. By its own nature, and it is assisted by competent interpreters, who may be accumulated in the philosopher himself, philosophy is able to lead an universal dialogue. Through the aspects that it transcends, philosophy keeps borders with science and with general culture; through those that transcend it, philosophy keeps borders with theology. That, philosophy owes to the state, in which it is found, the historical conditions of revelation and faith.Em razĂŁo das diferenças das respectivas pertinencias, nĂŁo hĂĄ diĂĄlogo direto possĂ­vel entre ciĂȘncia e fĂ© teologal. NĂŁo hĂĄ nada de estranho nisso, pois o mesmo ocorre entre uma ciĂȘncia e outra, entre ciĂȘncia e filosofia e atĂ© entre ciĂȘncia e cultura geral. Cada ciĂȘncia Ă© uma estrutura fechada, fala apenas sua lĂ­ngua, ignorando as demais. Mas isso nĂŁo quer dizer que nĂŁo seja possĂ­vel o diĂĄlogo entre diversas espĂ©cies ou diversos gĂȘneros de discurso. É a mediação de intĂ©rpretes que o viabiliza, e a filosofia Ă© o seu agente privilegiado. Por sua natureza, e desde que assistida por intĂ©rpretes que podem estar acumulados no prĂłprio filĂłsofo, a filosofia Ă© apta a conduzir um diĂĄlogo universal. Por aquilo que ela transcende, a filosofia mantĂ©m fronteiras com as ciĂȘncias e com a cultura geral; por aquilo que a transcende, ela mantĂ©m fronteiras com a teologia. Esta Ășltima marca, ela a deve ao estado em que se encon tra, que Ă© de um regime histĂłrico de revelação e de fĂ©

    Jellyfish Polysaccharides for Wound Healing Applications

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    Jellyfishes are considered a new potential resource in food, pharmaceutical and biomedical industries. In these latter cases, they are studied as source of active principles but are also exploited to produce marine collagen. In the present work, jellyfish skin polysaccharides (JSP) with glycosaminoglycan (GAG) features were extracted from Rhizostoma pulmo, a main blooming species of Mediterranean Sea, massively augmented by climate leaded “jellyfishication” of the sea. Two main fractions of R. pulmo JSP (RP-JSPs) were isolated and characterized, namely a neutral fraction (RP-JSP1) and a sulphate rich, negatively charged fraction (RP-JSP2). The two fractions have average molecular weights of 121 kDa and 590 kDa, respectively. Their sugar composition was evaluated through LC-MS analysis and the result confirmed the presence of typical GAG saccharides, such as glucose, galactose, glucosamine and galactosamine. Their use as promoters of wound healing was evaluated through in vitro scratch assay on murine fibroblast cell line (BALB/3T3 clone A31) and human keratinocytes (HaCaT). Both RP-JSPs demonstrated an effective confluency rate activity leading to 80% of scratch repair in two days, promoting both cell migration and proliferation. Additionally, RP-JSPs exerted a substantial protection from oxidative stress, resulting in improved viability of treated fibroblasts exposed to H2O2. The isolated GAG-like polysaccharides appear promising as functional component for biomedical skin treatments, as well as for future exploitation as pharmaceutical excipients

    Optimized electro- and wet-spinning techniques for the production of polymeric fibrous scaffolds loaded with bisphosphonate and hydroxyapatite

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    This research activity was aimed at the development of composite bioactive scaffolds made of biodegradable three-arm branched-star poly(Δ-caprolactone) (∗PCL), hydroxyapatite nanoparticles (HNPs) and clodronate (CD), a bisphosphonate that has demonstrated efficacy in the treatment of various bone diseases and as an anti-inflammatory drug. During the experimental work, the processing conditions for the fabrication of fibrous meshes, by either electrospinning or wetspinning, were optimized. Stemming from a previous research activity on electrospinning of ∗PCL, ∗PCL/HNPs 3D meshes were developed, evaluating the influence of fabrication parameters on the fibres’ morphology. By exploiting the binding affinity of bisphosphonates for hydroxyapatite, a methodology was set up for obtaining a physical linkage between CD and HNPs, with the aim of having a dual bioactive system loaded into ∗PCL fibrous mats. Fibres loaded with either CD or CD–HNP particles were thus produced and analysed by scanning electron microscopy for their morphology and by energy dispersive X-ray spectroscopy for their elemental compositionThis work was done within the framework of the European Network of Excellence 'EXPERTISSUES', Project No. NMP3-CT-2004-500283. Professor Ramani Narayan of Michigan Biotechnology Institute and Dr Fabio Neggiani of Abiogen Pharma-Pisa are acknowledged for supplying *PCL and CD, respectively

    Further Step in the Transition from Conventional Plasticizers to Versatile Bioplasticizers Obtained by the Valorization of Levulinic Acid and Glycerol

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    Valorization of glycerol and levulinicacid by a solvent-freeand mild-condition reaction to obtain a high-efficiency bioplasticizersuitable for different polymers.In the last two decades,the use of phthalates has beenrestrictedworldwide due to their well-known toxicity. Nonetheless, phthalatesare still widely used for their versatility, high plasticization effect,low cost, and lack of valuable alternatives. This study presents thefully bio-based and versatile glycerol trilevulinate plasticizer (GT)that was obtained by the valorization of glycerol and levulinic acid.The mild-conditions and solvent-free esterification used to synthesizeGT was optimized by investigating the product by Fourier transforminfrared and NMR spectroscopy. An increasing content of GT, from 10to 40 parts by weight per hundred parts of resin (phr), was testedwith poly(vinyl chloride), poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(lactic acid), and poly(caprolactone),which typically present complicatedprocessability and/or mechanical properties. GT produced a significantplasticization effect on both amorphous and semicrystalline polymers,reducing their glass-transition temperature and stiffness, as observedby differential scanning calorimetry measurements and tensile tests.Remarkably, GT also decreased both the melting temperature and crystallinitydegree of semicrystalline polymers. Furthermore, GT underwent enzyme-mediatedhydrolysis to its initial constituents, envisioning a promising prospectivefor environmental safety and upcycling. Furthermore, 50% inhibitoryconcentration (IC50) tests, using mouse embryo fibroblasts,proved that GT is an unharmful alternative plasticizer, which makesit potentially applicable in the biomedical field

    Clinical and laboratorial study of 19 cases of mucopolysaccharidoses

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    The mucopolysaccharidoses (MPS) are a heterogeneous group of inborn errors of lysosomal glycosaminoglycan (GAG) metabolism. The importance of this group of disorders among the inborn errors of metabolism led us to report 19 cases. METHOD: We performed clinical, radiological, and biochemical evaluations of the suspected patients, which allowed us to establish a definite diagnosis in 19 cases. RESULTS: Not all patients showed increased GAG levels in urine; enzyme assays should be performed in all cases with strong clinical suspicion. The diagnosis was made on average at the age of 48 months, and the 19 MPS cases, after a full clinical, radiological, and biochemical study, were classified as follows: Hurler -- MPS I (1 case); Hunter -- MPS II (2 cases); Sanfilippo -- MPS III (2 cases); Morquio -- MPS IV (4 cases); Maroteaux-Lamy -- MPS VI (9 cases); and Sly -- MPS VII (1 case). DISCUSSION: The high relative frequency of Maroteaux-Lamy disease contrasts with most reports in the literature and could express a population variability.As mucopolissacaridoses (MPS) constituem um grupo de erros inatos do metabolismo lisossomal dos glicosaminoglicanos (GAG) bastante heterogĂȘneo. A importĂąncia das MPS levou-nos a relatar as caracterĂ­sticas de 19 casos. MÉTODO: Realizamos uma avaliação clĂ­nica, radiolĂłgica e bioquĂ­mica, incluindo estudos enzimĂĄticos, que nos permitiram estabelecer o diagnĂłstico definitivo em 19 casos. RESULTADOS: Nem todos os pacientes apresentaram nĂ­veis elevados de GAG na urina, devendo os ensaios enzimĂĄticos serem realizados em todos os pacientes com forte suspeita clĂ­nica. O diagnĂłstico foi estabelecido em mĂ©dia aos 48 meses de idade e os casos, apĂłs amplo estudo clĂ­nico, radiolĂłgico e bioquĂ­mico, foram classificados como: Hurler -- MPS I (1 caso); Hunter -- MPS II (2 casos); Sanfilippo -- MPS III (2 casos); Morquio -- MPS IV (4 casos); Maroteaux-Lamy -- MPS VI (9 casos); e Sly -- MPS VI (1 caso). DISCUSSÃO: A proporção relativamente alta de MPS VI (Maroteaux-Lamy) contrasta com a maioria dos dados da literatura e pode expressar uma variabilidade populacional

    Working directly with probabilities in quantum field theory

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    We present a novel approach to computing transition probabilities in quantum field theory, which allows them to be written directly in terms of expectation values of nested commutators and anti-commutators of field operators, rather than squared matrix elements. We show that this leads to a diagrammatic expansion in which the retarded propagator plays a dominant role. As a result, one is able to see clearly how faster-than-light signalling is prevented between sources and detectors. Finally, we comment on potential implications of this approach for dealing with infra-red divergences

    Nanostructured 3D Constructs Based on Chitosan and Chondroitin Sulphate Multilayers for Cartilage Tissue Engineering

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    Nanostructured three-dimensional constructs combining layer-by-layer technology (LbL) and template leaching were processed and evaluated as possible support structures for cartilage tissue engineering. Multilayered constructs were formed by depositing the polyelectrolytes chitosan (CHT) and chondroitin sulphate (CS) on either bidimensional glass surfaces or 3D packet of paraffin spheres. 2D CHT/CS multi-layered constructs proved to support the attachment and proliferation of bovine chondrocytes (BCH). The technology was transposed to 3D level and CHT/CS multi-layered hierarchical scaffolds were retrieved after paraffin leaching. The obtained nanostructured 3D constructs had a high porosity and water uptake capacity of about 300%. Dynamical mechanical analysis (DMA) showed the viscoelastic nature of the scaffolds. Cellular tests were performed with the culture of BCH and multipotent bone marrow derived stromal cells (hMSCs) up to 21 days in chondrogenic differentiation media. Together with scanning electronic microscopy analysis, viability tests and DNA quantification, our results clearly showed that cells attached, proliferated and were metabolically active over the entire scaffold. Cartilaginous extracellular matrix (ECM) formation was further assessed and results showed that GAG secretion occurred indicating the maintenance of the chondrogenic phenotype and the chondrogenic differentiation of hMSCs

    Punishment in the Frame: Rethinking the History and Sociology of Art

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    Images of punishment have featured prominently in Western art and this article explores what might be learnt from studying such pictures of suffering. It seeks to develop an approach to the visual that avoids both the essentialism of art history and the reductionism of sociology by offering a rethinking of the relationships between the two. It begins by setting out the current state of the sociology of art, before discussing ‘new’ art histories that are inspired by social analysis. It then concentrates on how images of punishment have featured in Western art. This substantive material provides a rich resource to understand the force of representation and offers an opportunity to develop an aesthetic sociology that avoids some of the problems identified in the article. The approach developed in the second part is one that seeks to elaborate an aesthetic sociology that combines a historical sensitivity to images with the analytical concerns of social science. It strives to extend the art historian Michael Baxandall’s writings toward more sociological interpretations of visual analysis

    Direct In Vivo Cell Lineage Analysis in the Retrorsine and 2AAF Models of Liver Injury after Genetic Labeling in Adult and Newborn Rats

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    BACKGROUNDS AND AIMS:When hepatocyte proliferation is impaired, liver regeneration proceeds from the division of non parenchymal hepatocyte progenitors. Oval cells and Small Hepatocyte-like Progenitor Cells (SHPCs) represent the two most studied examples of such epithelial cells with putative stem cell capacity. In the present study we wished to compare the origin of SHPCs proliferating after retrorsine administration to the one of oval cells observed after 2-Acetyl-Amino fluorene (2-AAF) treatment. METHODOLOGY/PRINCIPAL FINDINGS:We used retroviral-mediated nlslacZ genetic labeling of dividing cells to study the fate of cells in the liver. Labeling was performed either in adult rats before treatment or in newborn animals. Labeled cells were identified and characterised by immunohistochemistry. In adult-labeled animals, labeling was restricted to mature hepatocytes. Retrorsine treatment did not modify the overall number of labeled cells in the liver whereas after 2-AAF administration unlabeled oval cells were recorded and the total number of labeled cells decreased significantly. When labeling was performed in newborn rats, results after retrorsine administration were identical to those obtained in adult-labeled rats. In contrast, in the 2-AAF regimen numerous labeled oval cells were present and were able to generate new labeled hepatocytes. Furthermore, we also observed labeled biliary tracts in 2-AAF treated rats. CONCLUSIONS:Our results strongly suggest that SHPCs are derived from hepatocytes and we confirm that SHPCs and oval cells do not share the same origin. We also show that hepatic progenitors are labeled in newborn rats suggesting future directions for in vivo lineage studies
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